Henrich V C
Department of Biology, University of North Carolina-Greensboro 27412, USA.
Arch Insect Biochem Physiol. 1995;30(2-3):239-54. doi: 10.1002/arch.940300212.
In both Manduca sexta and Drosophila melanogaster, metamorphic events are driven by ecdysteroids whose production in prothoracic gland (PGs) is stimulated periodically by neural factors. Differences in the life cycle of moths and flies have made it difficult to compare the regulation of ecdysteroid biosynthesis in these two species. As in Manduca, at least two neural factors in the larval Drosophila BVG complex were separable by molecular weight, and they stimulated increased ecdysteroid biosynthesis from the ring gland, a composite organ that includes PG cells. Drosophila neural extracts accelerated ecdysteroid biosynthesis in Manduca PGs and, conversely, partially purified Manduca PTTH preparations elevated ecdysteroid biosynthesis in Drosophila ring glands, suggesting that the two species may share structurally similar prothoracicotropic factors. Drosophila ring glands required the presence of calcium ions to respond to neural extracts, but the phosphodiesterase inhibitor MIX and cAMP analogues exerted little, if any, positive effect on production. Mean ecdysteroid production rates of BVG-ring gland complexes taken from Drosophila larvae during various phases of the wandering period were often submaximal and highly variable, suggesting that they fluctuate widely prior to pupariation. Based on available data in Drosophila and the Manduca model for the control of ecdysteroid biosynthesis, a developmental scheme for neuroendocrine control in Drosophila is proposed.
在烟草天蛾和黑腹果蝇中，变态事件是由蜕皮甾体驱动的，前胸腺（PGs）中蜕皮甾体的产生受到神经因子的周期性刺激。蛾类和蝇类生命周期的差异使得比较这两个物种中蜕皮甾体生物合成的调控变得困难。与烟草天蛾一样，果蝇幼虫BVG复合体中的至少两种神经因子可以通过分子量分离，并且它们刺激了来自环腺（一种包括PG细胞的复合器官）的蜕皮甾体生物合成增加。果蝇神经提取物加速了烟草天蛾PGs中的蜕皮甾体生物合成，反之，部分纯化的烟草天蛾促前胸腺激素（PTTH）制剂提高了果蝇环腺中的蜕皮甾体生物合成，这表明这两个物种可能共享结构相似的促前胸腺激素因子。果蝇环腺需要钙离子的存在才能对神经提取物做出反应，但磷酸二酯酶抑制剂MIX和cAMP类似物对产量几乎没有（如果有的话）积极影响。在漫游期的各个阶段从果蝇幼虫中取出的BVG - 环腺复合体的平均蜕皮甾体产生率通常低于最大值且变化很大，这表明它们在化蛹前波动很大。基于果蝇和烟草天蛾模型中关于蜕皮甾体生物合成控制的现有数据，提出了果蝇神经内分泌控制的发育方案。
